JP2007329316A - Wiring substrate and mounting structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wiring substrate capable of improving the reliability of electric connection between a wiring substrate and a mounting structure, whereby an yield of the mounting structure is improved and the manufacturing cost is reduced. <P>SOLUTION: The wiring substrate 3 is provided with a flexible substrate 30, a projection 31 provided on the substrate 30 and consisting of a resin, a conductive unit 32 provided on the projection 31, and a wiring 33 electrically connected to the conductive unit 32. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wiring board used for a personal computer, a mobile phone, and the like, and a mounting structure formed by mounting the wiring board on a mounting object such as an electro-optical panel.

2. Description of the Related Art Generally, a structure including an electro-optical panel and a wiring board mounted on the electro-optical panel is known as an electro-optical device mounted on an electronic apparatus such as a mobile phone, a notebook computer device, and a television receiver. . In this electro-optical device, a plurality of input terminals are arranged in a line at the edge of the electro-optical panel, and a plurality of connection terminals are arranged in a line corresponding to the input terminals at the edge of the wiring board. And an input terminal and a connection terminal are opposingly arranged through an anisotropic conductive member, and a corresponding input terminal and a connection terminal are each electrically connected by applying a heat | fever and a pressure with a tool. As the anisotropic conductive member, a material in which conductive particles are dispersed in an insulating resin is used, and an input terminal and a connection terminal are electrically connected through the conductive particles (for example, Patent Document 1). reference).
JP 2001-185263 A

  However, with the recent increase in definition of electro-optical devices, it is required to reduce the pitch of wirings and input terminals provided in the electro-optical panel. The pitch is also required to be narrowed. On the other hand, since the size of the conductive particles that connect them cannot be reduced so much, when the pitch of the connection terminals is reduced, the size of the conductive particles approaches the pitch between the connection terminals, and the electrical May cause a short circuit. Further, in order to increase the connection reliability between the input terminal and the connection terminal, it is necessary to make the conductive particles interposed between them slightly pressed and elastically deformed. However, if the size of the conductive particles is reduced, it is sufficient. There is also a problem that it is difficult to ensure the amount of elastic deformation, which increases the manufacturing cost.

  The present invention has been made in view of such circumstances, and in the case of mounting a wiring board on a mounting object, the reliability of electrical connection between the two can be improved, and the mounting structure obtained thereby An object of the present invention is to provide a wiring board and a mounting structure capable of improving the yield of the body and reducing the manufacturing cost.

In order to solve the above problems, a wiring board of the present invention includes a flexible base, a protrusion made of a resin provided on the base, a conductive part provided on the protrusion, And a wiring electrically connected to the conductive portion.
According to this configuration, the wiring board and the mounting object on which the wiring board is mounted are electrically connected via the conductive portion provided on the wiring board. In this case, since the conductive portion that contacts the mounting target is provided on the protrusion made of resin, when the conductive portion contacts the mounting target, the protrusion made of resin that is the base of the conductive portion. Due to the elastic action of the part, the conductive part can make good contact with the mounting object. Further, in this wiring board, since the conductive portion is in direct contact with the mounting object, it is not necessary to use an anisotropic conductive member containing conductive particles when connecting to the mounting object, and the wiring can be narrowed. It will be able to respond. Furthermore, since the protrusion is elastically deformed, the warp of the substrate generated when the wiring board is mounted on the mounting object can be absorbed by the protrusion, and a mounting structure with few mounting defects can be provided.

In the present invention, it is desirable that the conductive portion includes a plurality of conductive films arranged along a predetermined arrangement axis.
According to this configuration, it is possible to configure a terminal group including a plurality of terminals each using each conductive film as one terminal. In this case, since the pitch of each terminal can be reduced by a normal photolithography technique, the obtained wiring board is also a small wiring board.

In the present invention, the conductive film preferably includes a first conductive film made of the same conductive material as the wiring and a second conductive film made of a conductive material having higher corrosion resistance than the first conductive film. .
According to this configuration, since the wiring and the first conductive film can be integrally formed, the manufacturing becomes easier as compared with the case where they are formed by separate members. Moreover, since the 2nd electrically conductive film with high corrosion resistance is provided in the surface of the 1st electrically conductive film, high connection reliability can be acquired between mounting objects.

In the present invention, it is desirable that an insulating protective film covering the wiring is provided in a region other than the region where the conductive film is provided.
According to this configuration, a highly reliable wiring board can be provided by providing a highly corrosion-resistant protective film such as a coverlay or a solder resist on the surface of the wiring.

In the present invention, it is preferable that the protrusion includes a plurality of protrusions arranged along the predetermined arrangement axis corresponding to the plurality of conductive films.
According to this configuration, since the projections are provided separately for each conductive film, the deformation is projected when the wiring board is deformed by heat and pressure, compared to the case where the projections are continuously formed. Makes it easier to absorb.

In the present invention, it is preferable that the protrusion extends in a direction intersecting with the predetermined arrangement axis, and at least a part of the wiring is provided on a surface of the protrusion.
According to this configuration, the deformation of the wiring board caused by heat and pressure can be absorbed also by the protrusion provided on the wiring portion. In addition, since the portion where the wiring is formed and the portion where the conductive film is formed have the same configuration, they can be formed in a common process, which facilitates manufacture.

In the present invention, it is desirable that the protrusion is formed of a photosensitive resin.
According to this configuration, it is not necessary to use a resist mask or the like in order to form the protrusions, so that manufacturing is facilitated.

In the present invention, it is preferable that the base material is formed of the same resin as the protrusions, and the protrusions are formed by processing the surface of the base material.
According to this configuration, since the protruding portion and the substrate can be integrated, there is no problem such as peeling of the protruding portion. In addition, the manufacturing cost can be reduced as compared with the case where the protrusion is formed of a separate member.

The mounting structure of the present invention is a mounting structure in which a mounting object and a wiring board are electrically connected, and the wiring board is provided on a flexible base material and the base material. A protrusion made of a resin, a conductive film provided on the protrusion, and a wiring provided on the protrusion and electrically connected to the conductive film, the wiring board and the mounting object Is directly contacted and electrically connected via the conductive film, and the protrusions in the portion where the conductive film is provided are elastically deformed and become thinner than the protrusions in other portions. It is characterized by.
According to this configuration, the conductive film can satisfactorily come into contact with the mounting target object due to the elastic action of the protrusions made of the resin that is the base of the conductive film. In addition, since the conductive film is in direct contact with the mounting target, there is no need to use an anisotropic conductive member containing conductive particles when connecting to the mounting target, and the wiring can be made narrower. Become. Furthermore, since the protrusions are elastically deformed, the warp of the substrate generated when the wiring board is mounted on the mounting target can be absorbed by the protrusions, and a mounting structure with few mounting defects can be provided.

In the present invention, an insulating adhesive that does not include conductive particles is provided between the wiring board and the mounting object, and the relative position between the wiring board and the mounting object is fixed by the adhesive. It is desirable that
According to this structure, compared with the case where the adhesive agent containing electroconductive particle is used, reduction of manufacturing cost is achieved and the electrical short circuit which arises between electrically conductive films can also be prevented.

  Embodiments of the present invention will be described below with reference to the drawings. This embodiment shows one aspect of the present invention, and does not limit the present invention, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each structure easy to understand, an actual structure and a scale, a number, and the like in each structure are different.

  In the following description, an XYZ orthogonal coordinate system is set, and the positional relationship of each member will be described with reference to this XYZ orthogonal coordinate system. At this time, the predetermined direction in the horizontal plane is the X-axis direction, the direction orthogonal to the X-axis direction in the horizontal plane is the Y-axis direction, and the direction orthogonal to each of the X-axis direction and the Y-axis direction (that is, the vertical direction) is the Z-axis direction. And

[First Embodiment]
FIG. 1 is an exploded perspective view of an electro-optical device that is an example of a mounting structure including a wiring board according to the present invention. As shown in FIG. 1, the electro-optical device 1 includes an electro-optical panel 2 as an object to be mounted, and a wiring board 3 electrically connected to the electro-optical panel 2. In addition to the wiring substrate 3, the electro-optical panel 2 is provided with a lighting device such as a backlight and other ancillary equipment as necessary, but the illustration thereof is omitted in FIG.

  The electro-optical panel 2 includes a first substrate 4a and a second substrate 4b facing the first substrate 4a. On one surface of these substrates 4a and 4b, a sealing material 6 is formed in a substantially rectangular frame shape by printing or the like. By this sealing material 6, the first substrate 4a and the second substrate 4b are formed. It is pasted together. A gap maintained by a spacer (not shown), that is, a so-called cell gap is formed between the first substrate 4a and the second substrate 4b bonded together by the sealing material 6, and the liquid crystal 9 is sealed in the cell gap. Yes. A part of the sealing material 6 is provided with an opening 7 for liquid crystal injection in advance. The opening 7 is sealed with resin or the like after the liquid crystal 9 is injected.

  The first substrate 4a has a transparent base made of glass, plastic or the like and has a substantially rectangular shape when viewed from the Z-axis direction, and the surface of the base on the liquid crystal 9 side (the surface on the + Z side) The plurality of first electrodes 17a are formed to be parallel to each other along the X-axis direction. The second substrate 4b facing the first substrate 4a has a transparent base material that is formed of glass, plastic, or the like and has a substantially rectangular shape when viewed from the Z-axis direction. A plurality of second electrodes 17b are formed on the surface (the surface on the −Z side) so as to be parallel to each other along the Y-axis direction. An alignment film (not shown) is formed on the surfaces of the first electrode 17a and the second electrode 17b as a film having a uniform thickness, for example, using polyimide as a material.

  The portion where the first electrode 17a and the second electrode 17b intersect constitutes a minimum unit of display, that is, a display dot, and the entire display region is formed by arranging a plurality of display dots in a matrix. Yes. Each display dot is provided with a switching element such as a TFD (Thin Film Diode) as necessary, and a plurality of display dots are driven in matrix by the switching element.

  In FIG. 1, the interval between the electrodes is drawn wider than the actual distance in order to show the arrangement state of the first electrode 17a and the second electrode 17b in an easy-to-understand manner. As for 17b, many books are formed on a base material by a narrower space | interval.

  The first substrate 4a has a portion 4c projecting to the outside of the second substrate 4b, and driving ICs 22a, 22b, and 22c are mounted on the projecting portion 4c using, for example, ACF (Anisotropic Conductive Film). . The input terminals of the driving ICs 22a, 22b, and 22c are electrically connected to an external connection terminal 23 formed on the side edge of the overhanging portion 4c of the first substrate 4a.

  The output terminal of the driving IC 22b located at the center of the overhang portion 4c is directly connected to the first electrode 17a formed on the first substrate 4a. Further, the driving ICs 22a and 22c mounted in the regions on both sides of the overhanging portion 4c are connected to the second electrode 17b formed on the second substrate 4b via a conductive material (not shown) included in the sealing material 6. Electrically connected.

  The wiring board 3 includes a flexible plastic base 30 and a plurality of wirings 33 and 38 provided on the base 30. A plurality of terminals 37 are provided on the side edge of the base 30 on the electro-optical panel 2 side, and a plurality of terminals 39 are provided on the side edge opposite to the electro-optical panel 2. Although not shown, a plurality of electronic components including an IC package or the like are mounted on the central portion of the wiring board 3, and the plurality of electronic components are electrically connected to the wirings 33 and 38. Yes.

  The terminals 39 are arranged along an arrangement axis parallel to the X axis. The plurality of terminals 39 form an input side terminal group. The plurality of terminals 39 are connected to an external control circuit (not shown), for example, a control circuit included in an electronic device such as a mobile phone or a portable information terminal. When a signal is supplied from the external control circuit to the wiring board 3 via the terminal 39, a predetermined signal is supplied to the driving ICs 22a, 22b, and 22c, whereby the display by the electro-optical panel 2 is performed.

  The terminal 39 is directly connected to the wiring 38. The wiring 38 is formed in a stripe shape as a whole by arranging a plurality of linear electrodes extending in the Y-axis direction in parallel with each other. These wirings 38 are directly or indirectly connected to the wirings 33 through electronic components at the center of the wiring board 3. The wiring 33 is formed in a stripe shape as a whole by arranging a plurality of linear electrodes extending in the Y-axis direction in parallel with each other.

  A terminal 37 is provided at the tip of the wiring 33. The terminals 37 are arranged along an arrangement axis parallel to the X axis, and an output side terminal group is formed by the plurality of terminals 37. The plurality of terminals 37 are connected to the external connection terminals 23 of the electro-optical panel 2 so that the wiring board 3 and the electro-optical panel 2 are electrically connected.

  FIG. 2 is a partial perspective view showing the side edge of the wiring board 3 on the electro-optical panel 2 side. As shown in FIG. 2, the wiring board 3 includes a flexible base material 30, a protrusion 31 made of a resin provided on the base 30, and a conductive part 32 provided on the protrusion 31. And a wiring 33 electrically connected to the conductive portion 32.

  The protrusion 31 includes a plurality of protrusions 34 provided corresponding to the wiring 33. The protrusions 34 are formed in a stripe shape as a whole by arranging a plurality of linear protrusions extending in the Y-axis direction in parallel with each other along an array axis parallel to the X-axis. The protrusions 34 are made of an elastic resin material such as polyimide resin, acrylic resin, phenol resin, epoxy resin, or silicone resin. The protrusion 34 is preferably formed of a photosensitive resin. In this case, it is not necessary to use a resist mask or the like in order to form the protrusions 34, so that the manufacturing becomes easy.

  The conductive portion 32 includes a plurality of conductive films 36 arranged along an arrangement axis parallel to the X axis. The conductive film 36 includes a first conductive film 33 provided on the protrusion 34 and a second conductive film 35 provided on the first conductive film 33. The first conductive film 33 is formed in a stripe shape as a whole by arranging a plurality of linear first conductive films extending in the Y-axis direction in parallel with each other along an array axis parallel to the X-axis. A wiring 33 is formed by the first conductive film extending from the side edge of the base material 30 into the base material 30. For example, Cu is used as the conductive material of the first conductive film 33.

  The second conductive film 35 is made of a metal having better conductive contact than the first conductive film 33 such as Au, Ni—Au, or Sn. The second conductive film 35 is formed on the first conductive film 33 by a technique such as plating. The second conductive film 35 is provided only at the side edge of the base material 30, and the terminal 37 is formed by the protrusion 34, the first conductive film 33, and the second conductive film 35 in the portion where the second conductive film 35 is provided. Is formed. A protective film 40 generally called a cover lay or a solder resist is provided in a region other than the region where the conductive film 36 is provided, and the wiring 33 is covered with the protective film 40. As the protective film 40, a material having high corrosion resistance such as polyimide resin is used.

  Although explanation is omitted, the terminal 39 and the wiring 38 provided at the side edge of the wiring board 3 opposite to the electro-optical panel 2 have the same configuration as the terminal 37 and the wiring 33. That is, a protrusion made of resin is provided on the base material 30 corresponding to the terminal 39 and the wiring 38, and a conductive film is provided on the surface thereof, thereby forming a terminal and a wiring having a resin core.

  FIG. 3 is a cross-sectional view showing a connection structure between the wiring board 3 and the electro-optical panel 2. As shown in FIG. 3, the edge part of the wiring board 3 in which the terminal 37 was formed is joined to the edge part of the overhang | projection part 4c of the 1st board | substrate 4a by thermocompression bonding. The first substrate 4a and the wiring substrate 3 are bonded by the adhesive 61, and the adhesive 61 is cured in a state where the protrusion 34 is compressed and deformed, so that the relative position between the first substrate 4a and the wiring substrate 3 is fixed. Is done. In this case, the thickness of the projection 34 in the portion where the terminal 37 is provided is thinner than the thickness of the projection 34 in the portion where the wiring 33 is provided, and the repulsive force causes the conductive film 34 of the terminal 37 to be connected to the external connection terminal 23. Therefore, the reliability of electrical connection is improved.

  As the adhesive 61, an insulating adhesive that does not contain conductive particles such as NCF (Non Conductive Film) is used. Thereby, compared with the case where an adhesive containing conductive particles such as ACF (Anisotropic Conductive Film) is used, the manufacturing cost is reduced, and an electrical short circuit between the conductive films is also prevented. be able to.

  As described above, in the electro-optical device 1 according to the present embodiment, the terminal 37 of the wiring board 3 is formed with the protrusion 34 made of resin as a core. Therefore, the conductive film 36 is electrically connected by the elastic action of the protrusion 34. Good contact with the optical panel 2 can be achieved. In addition, since the conductive film 36 is in direct contact with the electro-optical panel 2, it is not necessary to use an anisotropic conductive member containing conductive particles when connecting to the electro-optical panel 2, and the wiring 33 can be narrowed. It will be possible. Further, since the protrusions 34 are elastically deformed, the warp of the substrate generated when the wiring board 3 is mounted on the electro-optical panel 2 can be absorbed by the protrusions 34, and the electro-optical device 1 with few mounting defects can be provided.

  Further, since the projections 34 are provided separately for each conductive film 36, the projections 34 can easily absorb the deformation generated in the wiring board 3 due to heat and pressure. Furthermore, since the protrusion 34 is formed along the wiring 33 to the inside of the terminal 37, the deformation of the wiring board 3 can be absorbed also by the protrusion 34 provided in the wiring portion. In addition, since the portion where the wiring 33 is formed and the portion where the conductive film 36 is formed (the portion of the first conductive film 33) have the same configuration, they can be formed in a common process, which facilitates manufacture.

[Second Embodiment]
Next, a second embodiment will be described. FIG. 4 is a partial perspective view of the wiring board according to the second embodiment. The basic configuration of this wiring board is the same as that of the wiring board 3 of the first embodiment shown in FIG. 2, except that the protrusions 41 are formed integrally with the base material 30. In this wiring board, the base material 30 and the protrusion 41 are made of the same resin. The surface of the base material 30 is processed by etching or the like, and the protrusion 41 is formed by the uneven shape of the base material 30 formed by this processing.

  According to this structure, since the protrusion 41 and the base material 30 can be integrated, there is no problem such as peeling of the protrusion 41. In addition, the manufacturing cost can be reduced as compared with the case where the protrusion 41 is formed of a separate member.

[Third Embodiment]
Next, a third embodiment will be described. FIG. 5 is a partial perspective view of the wiring board according to the third embodiment. In this wiring board, the protrusion 51 is provided at the (+ Y side) end on the base material 30 so as to be able to support each of the plurality of conductive films 36, that is, each of the plurality of conductive films 36. As described above, the terminals 37 are provided along the X axis which is the arrangement axis of the terminals 37. The surface of the protrusion 51 is formed in an arc shape in cross section so as to swell toward the opposite side of the base material 30, that is, toward the upper side (+ Z side), and is formed in a bowl shape as a whole.

  This configuration is the same as that of the wiring board of the first embodiment except that the protrusion 51 is not provided in the wiring 33 and the protrusion 51 is not provided separately for each conductive film 36. The same. Therefore, also in this wiring board, the same effect as the first embodiment can be obtained. In addition, since the protrusion 51 of the wiring board is formed in an arc shape in cross section, good adhesion can be obtained when connecting to the electro-optical panel.

  In FIG. 5, the plurality of conductive films 36 are formed on the common protrusion 51, but the protrusions 51 may be formed separately for each conductive film 36. In this case, even when the wiring substrate is deformed by heat and pressure when connected to the electro-optical panel, the deformation is easily absorbed by the protrusions.

[Electronics]
FIG. 6 is a diagram illustrating an example of an electronic apparatus including the above-described electro-optical device. The electronic apparatus shown here includes a display information output source 101, a display information processing circuit 102, a power supply circuit 103, a timing generator 104, and an electro-optical device 105. The electro-optical device 105 includes an electro-optical panel 107 and a drive circuit 106.

  The display information output source 101 includes a memory such as a RAM (Random Access Memory), a storage unit such as various disks, a tuning circuit that tunes and outputs a digital image signal, and various clock signals generated by the timing generator 104. The display information processing circuit 102 is supplied with display information such as a predetermined format image signal.

  Next, the display information processing circuit 102 includes a number of well-known circuits such as an amplification / inversion circuit, a rotation circuit, a gamma correction circuit, a clamp circuit, and the like, executes processing of input display information, and outputs an image signal. It is supplied to the drive circuit 106 together with the clock signal CLK. Here, the drive circuit 106 is a general term for an inspection circuit and the like together with a scanning line drive circuit (not shown) and a data line drive circuit (not shown). The power supply circuit 103 supplies a predetermined power supply voltage to each of the above components.

  The electro-optical device 105 can be configured similarly to the electro-optical device 1 illustrated in FIG. 1, for example. Since the electro-optical device 1 is excellent in connection reliability, an electronic device using the electro-optical device 1 is also excellent in electrical characteristics and can exhibit high display quality.

1 is an exploded perspective view of an electro-optical device including a wiring board according to a first embodiment. It is a fragmentary perspective view of the same wiring board. It is an expanded sectional view of the junction part of the same wiring board and an electro-optical panel. It is a fragmentary perspective view of the wiring board of 2nd Embodiment. It is a fragmentary perspective view of the wiring board of 3rd Embodiment. It is a figure which shows an example of the electronic device provided with the electro-optical apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electro-optical apparatus (mounting structure), 2 ... Electro-optical panel (mounting object), 3 ... Wiring board, 30 ... Base material, 31 ... Projection part, 32 ... Conductive part, 33 ... 1st electrically conductive film (wiring) , 34 ... projection, 35 ... second conductive film, 36 ... conductive film, 40 ... protective film, 41 ... projection, 51 ... projection, 61 ... adhesive

Claims (10)

A flexible substrate;
A protrusion made of a resin provided on the substrate;
A conductive portion provided on the protruding portion;
And a wiring board electrically connected to the conductive portion.   The wiring board according to claim 1, wherein the conductive portion includes a plurality of conductive films arranged along a predetermined arrangement axis.   The conductive film includes a first conductive film made of the same conductive material as that of the wiring and a second conductive film made of a conductive material having higher corrosion resistance than the first conductive film. Wiring board as described in.   The wiring substrate according to claim 2, wherein an insulating protective film that covers the wiring is provided in a region other than the region where the conductive film is provided.   5. The wiring board according to claim 2, wherein the protrusion includes a plurality of protrusions arranged along the predetermined arrangement axis corresponding to the plurality of conductive films. 6. The protrusion extends in a direction intersecting the predetermined array axis;
The wiring board according to claim 5, wherein at least a part of the wiring is provided on a surface of the protrusion.   The wiring board according to claim 1, wherein the protrusion is made of a photosensitive resin. The base material is formed of the same resin as the protrusion,
The wiring board according to claim 1, wherein the protrusion is formed by processing a surface of the base material. A mounting structure in which a mounting object and a wiring board are electrically connected,
The wiring board includes a flexible base, a protrusion made of a resin provided on the base, a conductive film provided on the protrusion, and a conductive film provided on the protrusion. Connected to each other, and
The wiring board and the mounting object are directly contacted and electrically connected via the conductive film, and the protrusions of the portion where the conductive film is provided are elastically deformed, A mounting structure having a thickness smaller than that of the protrusion. An insulating adhesive containing no conductive particles is provided between the wiring board and the mounting object, and the relative position between the wiring board and the mounting object is fixed by the adhesive. The mounting structure according to claim 9, wherein

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